I am pretty new with Ubuntu (I normally use Windows, but for my new work I use Ubuntu on a Dell laptop) and I am having some problems with frequent freezing and the detection of external monitors.
When I first started using the laptop (Dell Latitude 7490 with UHD graphics 620) it very frequently froze after waking up from sleep, which got quite annoying, so I started looking around for a solution.
I ended up trying many different things, and at some point, I unfortunately came to the conclusion that updating the system from Ubuntu 20.10 to 21.04 could resolve the problem, but it still persisted.
Having looked around, I heard that setting
nomodeset on boot would resolve the problems with freezes, which worked for a while. However, now my external monitor (using HDMI) wouldn’t get recognized any more, so my search continued.
I removed the
nomodeset, disabled Secure Boot in UEFI, and increased the swap size to 8Gb (8 counts of block sizes of 1Gb) which again resolved most of the freezes, but still my external monitor could not be recognized. I don’t know what removed my ability to use the external monitor and the laptop sometimes freeze when waking up..
xrandr now outputs:
xrandr: Failed to get size of gamma for output default
Screen 0: minimum 1920 x 1080, current 1920 x 1080, maximum 1920 x 1080
default connected primary 1920x1080+0+0 0mm x 0mm
Under Settings > Displays, the laptop monitor is called “Unknown Display” and I am not able to change any settings here.
My guess is that downgrading to 20.10 wouldn’t resolve my problems, but if I have to I can – I just prefer not to..